(May 16, 1975-September 11, 2001)
Born in Mecca, Saudi Arabia
One of the 19 hijackers of the 9/11 attacks
Hijacked American Airlines Flight 77, which crashed into the Pentagon
Served as a 'muscle' among the hijackers
Also known as Sinaan
Fought in Bosnian war on the Bosnian Muslim side (1995)
Also fought in Afghanistan and, according to some unconfirmed sources, Chechnya
Lived in San Diego with fellow hijacker and childhood friend Nawaf al-Hazmi (February-June 10, 2000)

Why he might be annoying

He and Nawaf spoke English poorly, so they didn't do well in flight lessons when they were trained to be pilots in San Diego.
Their neighbors said that they slept on mattresses, yet were always on their phones, carrying briefcases, and playing flight simulator games, which they used to hijack Flight 77 during 9/11.
Their flight instructor said they were 'impatient students'.
He was buddies with radical imam Anwar Al-Awlaki.
People who met him said he was 'dark and brooding, with a dislike of American culture'.

Why he might not be annoying

He was brainwashed into believing a distorted version of Islam that orders its followers to kill innocent people as part of jihad.
His family was related to the Quraysh tribe, which Muhammad belonged to.
He was nearly spared involvement in the attacks when Khalid Shaikh Mohammed decided to remove him from the 9/11 plot for leaving Nawaf alone, only to be overruled by Osama bin Laden.
He somehow proved that video games have a more practical side than mere entertainment.

For 2019, as of last week, Out of 1788 Votes: 70.97% Annoying
In 2018, Out of 891 Votes: 50.06% Annoying
In 2017, Out of 516 Votes: 80.04% Annoying
In 2016, Out of 126 Votes: 96.83% Annoying
In 2015, Out of 789 Votes: 65.02% Annoying